Non-traumatic myositis ossificans circumscripta at elbow joint in a 9-year old child

Myositis ossificans in the pediatric population: a systematic scoping review

Introduction

Circumscribed or pseudomalignant myositis ossificans (MO) is a rare and benign condition characterized by heterotopic bone formation in soft tissues. The clinical presentation of MO, imaging investigations, histological findings, and treatment strategies are unclear, especially in the pediatric population.

Materials and methods

A literature search was conducted in PubMed, Scopus, and Google Scholar electronic databases to identify original articles and reviews in English or French of traumatic and non-traumatic MO. Studies were selected by 2 independent reviewers following the PRISMA recommendation and descriptive data were extracted. We harvest in each case the sex, age at diagnosis, location, presence of initial trauma, pre-emptive diagnosis, modalities of imagery used, realized biopsy, treatment performed, and type of follow-up.

Results

Sixty pediatric cases of MO were identified between 2002 and 2023. Twenty-three patients (38.3%) were diagnosed with idiopathic/pseudomalignant and 37 patients (61.7%) with circumscribed. The mean age at diagnosis was 9.5 years (range 0.2-17 years), with a male-to-female ratio of 1:1. The initial pre-emptive diagnosis was neoplasia in 13 patients (21.7%). The biopsy was percutaneous in 9 patients (15%) and incisional in 7 patients (11.7%). Histological analysis was achieved in 35 cases (57%). Surgical excision was the first line treatment in 46.7% of patients, and non-surgical in the remaining patients. The follow-up strategy was clinical in 16 patients (26.7%) or based on imaging investigation in 23 patients (38.3%).

Discussion

Although MO in children is described as a rare pathology, identifying the benignity of the condition is essential to avoid unnecessary invasive treatment and to avoid delaying the treatment of a potentially life-threatening entity. It seems that there is no consensus established concerning the proper imaging for diagnosis. Clinicians should acknowledge that the absence of a triggering trauma tends to direct the investigation and the management toward a surgical attitude. Conservative management is key, however, surgical excision can be proposed on matured lesions on a case-by-case basis. The absence of recurrence is not excluded. Therefore, a close clinical follow-up is suggested for all cases. The true benefit of a radiological is questioned in a question known to be self-resolving.

Non-traumatic myositis ossificans

Myositis ossificans (MO) is a benign, ossifying lesion that usually affects the skeletal muscle. The rare non-traumatic form of MO can cause diagnostic dilemma and management issues. These lesions, however, have similar radiology and histopathological characteristics described in the more frequently encountered traumatic forms. Depending on the stage of the lesion, the inherent feature of myositis ossificans varies, and so does the management of the lesion. We describe a non-traumatic MO occurring in latissimus dorsi of a young girl and discuss the review of literature on this rare subtype.

A nontraumatic myositis ossificans case of the forearm: Case report and literature review

Myositis ossificans (MO) is a rare, benign ossifying lesion characterized by focal formation of heterotopic bone and cartilage in extraskeletal soft-tissue that most commonly occurs in young adults. In most cases, no causative factor can be identified. The diagnosis of MO is usually based on the patient's history of trauma, clinical signs, on imaging appearance and histological examination. We present a non-traumatic MO case of the forearm in a 40-year-old man with weakness in left finger motion, a decrease in prehension for more than three weeks, without any weight loss, malaise, anorexia or fever. The clinical symptoms and radiological findings can be easily confused with malignant lesions. Treatment is usually conservative but, due to the limited strength and range of motion of the left hand, the tumor was extirpated and the diagnosis of MO was made by biopsy. The patient had no neurological deficits after surgical treatment and was discharged on the fifth day after the surgery in good condition with the recommendation to begin a rehabilitation program.

Case Report: Unusual Presentation of Myositis Ossificans of the Elbow in a Child Who Underwent Excessive Postoperative Rehabilitation Exercise

Traumatic myositis ossificans (MO) is an unusual complication after muscle injury and is predominantly seen in young adults and adolescents. Pediatric MO cases are even rarer. We report an 8-year-old girl who was diagnosed with a lateral humeral condyle fracture. She was treated surgically, and her elbow joint was fixed with plaster. Rehabilitation exercise was administered 1 month after the operation. Due to the wrong exercise method, a palpable bony mass appeared around the elbow 1 month later. The clinical radiological diagnosis showed MO, and conservative treatment was administered. After 3 years of follow-up, the affected limb functioned well, with no sign of recurrence. Here, we report this long-term follow-up case of MO resulting from excessive rehabilitation exercise.

Ossifying myositis in the infant. About a case

Myositis ossificans is a benign disorder characterized by the formation of heterotopic bone in skeletal muscle or soft tissues. It is extremely rare in children, <1% of cases occur in children under 10 years. We present a 17-day-old boy that, after 10 days of Intermediate Care Unit stay, was referred to our hospital for a developmental dysplasia of the hip. On clinical examination, he had swelling on the left thigh and increase in size compared to the contralateral one, therefore was admitted for studying. Imaging findings including plain radiographs, CT, MRI and bone scintigraphy, as well as treatment performed, are described. To the best of our knowledge, is the youngest case reported in the literature.

Heterotopic ossification in a 7-year-old female patient treated with individualized homeopathy: A case report

Classical homeopathy can be included among the treatment options for congenital heterotopic ossification.

Two cases of myositis ossificans in children, after prolonged immobilization

Myossitis ossificans (MO) is a benign disorder characterized by heterotopic bone formation in skeletal muscle. It is divided in three types, fibrodysplasia ossificans progressive (FOP), myositis ossificans circumscripta or traumatica (MOT) and myositis ossificans without a history of trauma (non traumatic or pseudomalignant MO). Myositis ossificans is extremely rare in children younger than 10 years. We present the clinical and radiological findings of two 5-year-old children with pseudomalignant MO due to prolonged immobilization. Plain x-ray films and CT scan with their characteristic findings of mature bone in the periphery of the lesion with smooth contour and well separated from the bone, enabled us to diagnose the lesion. To the best of our knowledge, no such cases have been reported in the literature.